Seeing the forest through the trees: a systematic review of the safety and efficacy of combination chemotherapies used in the treatment of metastatic colorectal cancer

Perioperative Chemotherapy for Liver Metastasis of Colorectal Cancer: Lessons Learned and Future Perspectives

OPINION STATEMENT

Colorectal cancer (CRC) is a major public health problem and the 2nd leading-cause of cancer-related death worldwide. Around 30% of patients present with metastatic disease and 50% of those with early disease will eventually relapse. The metastatic spread occurs mainly to the liver, which is the exclusive site in 30-40% of the cases. Surgery is the main curative option for liver recurrence, but only one out of five patients are eligible for resection. Moreover, even if surgery is feasible, recurrence rate is high, occurring in up to 75% of patients. Therefore, additional treatment to improve these disappointing outcomes has been sought. Adjuvant and perioperative chemotherapy aim to eradicate early micrometastatic disease, decreasing recurrence rates, and improving survival outcomes. Different chemotherapy regimens, mainly extrapolated from the adjuvant experience, have showed conflicting results, with improvements in disease free but not in overall survival. The addition of targeted therapies to chemotherapy has improved response rates and resectability when administered preoperatively, but did not have an impact on survival in the adjuvant setting. There is a need to critically synthetize the available evidence on perioperative and conversion therapy from the past years, and appraise areas of current research and potential future directions.

Pushing the limit of liver regeneration - Safety and survival after monosegment-ALPPS: systematic review and individual patient data meta-analysis

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has expanded and spearheaded development in hepatobiliary surgery. Monosegment-ALPPS tests liver regeneration limits and may present as the last feasible curative treatment option.

METHODS

Electronic databases (MEDLINE, Web of Science, Google Scholar, Cochrane Library and WHO International Clinical Trials Registry Platform) were searched for publications on mono-ALPPS using a predefined strategy without date or language restrictions. Individual patient data was extracted and analyzed.

RESULTS

237 publications were identified. 19 patients were identified to have undergone mono-ALPPS. Primarily, mono-ALPPS has been utilized as curative treatment for CRLM (17 of 19 cases). Successful mono-ALPPS was possible in FLR above 8% SLV. All patients received either chemotherapy alone or in combination with radiotherapy prior to surgery. 8 of 19 patients experienced PHLF grade A or B. There was no in-hospital mortality described. Recurrent disease has occurred in 7 of 19 patients and 3 have died during follow-up.

CONCLUSION

Mono-ALPPS is an experimental procedure that provides a reasonably safe opportunity to curatively treat extensive liver malignancies in patients with FLR as low as 8% SLV. PHLF is the most prevalent complication in mono-ALPPS. Mono-ALPPS should be evaluated in a multicentral study setting.

Natural and synthetic retinoids in preclinical colorectal cancer models

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide. Although targeted therapy in combination with chemotherapy in CRC prolongs the overall survival of patients with metastatic disease, acquired resistance and relapse hinder their clinical benefits. Moreover, patients with some specific genetic profile are unlikely to benefit from targeted therapy, suggesting the need for safe and effective treatment strategies. Retinoids, comprising of natural and synthetic analogs, are a class of chemical compounds that regulate cellular proliferation, differentiation, and cell death. Retinoids have been used in the clinic for several leukemias and solid tumors, either as single agents or in combination therapy. Furthermore, retinoids have shown potent chemotherapeutic and chemopreventive properties in different cancer models, including CRC. In this review, we summarize the major preclinical findings in CRC in which natural and synthetic retinoids showed promising antitumor activities and stress on the proposed mechanisms of action. Understanding of the retinoids' antitumor mechanisms would provide insights to support and warrant their development in the management of CRC.

Pharmacological cancer treatment and venous thromboembolism risk

Risk factors for cancer-associated thrombosis are commonly divided into three categories: patient-, cancer-, and treatment-related factors. Currently, different types of drugs are used in cancer treatment. Chemotherapy has been identified as an independent risk factor for venous thromboembolism (VTE). However, it should be noted, that the risk of VTE is not consistent among all cytotoxic agents. In addition, different supportive care drugs, such as erythropoiesis stimulating agents or granulocyte colony stimulating factors, and hormonotherapy have been associated to an increased risk of VTE. Immunotherapy and molecular-targeted therapies have significantly changed the treatment of cancer over the past decade. The main subtypes include tyrosine-kinase inhibitors, monoclonal antibodies, small molecules, and immunomodulatory agents. The relationship between VTE and targeted therapies remains largely unknown.

Maintenance Versus Intermittent Strategies in the Treatment of Metastatic Colorectal Cancer: A Meta-Analysis from Another Angle

INTRODUCTION

Considering the differences in overall survival (OS) and progression-free survival (PFS), treatment options for metastatic colorectal cancer (mCRC) are still inconclusive. We carried out a meta-analysis of maintenance and intermittent strategies for the treatment of mCRC aiming at providing an accurate estimation of different treatments in increasing the chance and duration of survival.

METHODS

PubMed, Embase and CNKI were systematically searched. The pooled hazard ratio (HR) and 95% confidence interval (CI) were counted. We used STATA 12.0 and RevMan 5.2 for statistical analyses.

RESULTS

A total of six publications with a population of 1975 mCRC patients were included in our meta-analysis. Analysis of OS revealed a statistically significant benefit associated with maintenance therapy (HR: 0.86, 95% CI 0.75-0.98, P = 0.02). Comparing maintenance therapy with an intermittent strategy, the first progression-free survival (PFS1) showed no significant difference (HR, 0.77; 95% CI 0.48-1.24, P = 0.29), but maintenance therapy improved the second progression-free survival (PFS2) significantly (HR, 0.66; 95% CI 0.54-0.81, P < 0.001). Sensitivity analysis was carried out to assess the stability of results. No publication bias was detected during analysis.

CONCLUSION

Compared with the maintenance strategy, first-line chemotherapy that was completely stopped until disease progression did not benefit mCRC patients in terms of OS and PFS2. Therefore, a maintenance strategy is a good option for individualized mCRC patients.

The efficacy and safety of irinotecan ± bevacizumab compared with oxaliplatin ± bevacizumab for metastatic colorectal cancer: A meta-analysis

BACKGROUND

Irinotecan (IRI)-based and oxaliplatin (OXA)-based regimens are available for the treatment of metastatic colorectal cancer (mCRC). Several studies have published inconsistent results in their comparisons of the efficacy and toxicity of IRI ± bevacizumab and OXA ± bevacizumab. This meta-analysis was performed to evaluate the efficacy and safety of these 2 regimens in patients with mCRC.

METHODS

We searched several databases to identify relevant studies, including PubMed, EMBASE, and the Cochrane Controlled Trials Register. The primary endpoints were overall survival (OS) and time to progression (TTP). The secondary comparisons were overall response rate (ORR) and toxicity. In addition, the hazard ratio (HR) or risk ratio (RR) values with their corresponding 95% confidence intervals (CIs) were extracted from these studies.

RESULTS

Pooled data of 13 studies demonstrated no significant differences in OS (HR = 0.96, 95% CI: 0.86-1.08, P = .53) and TTP (HR = 0.88, 95% CI: 0.72-1.08, P = .24) between the 2 groups. However, the ORR (RR = 0.87, 95% CI: 0.78-0.97, P = .02) was clearly improved in the OXA ± bevacizumab arm. Higher incidences of grade 3/4 nausea (RR = 1.63, 95% CI: 1.28-2.07, P < .001), vomiting (RR = 1.40, 95% CI: 1.09-1.81, P = .01), diarrhea (RR = 1.44, 95% CI: 1.23-1.70, P < .001), and anemia (RR = 4.13, 95% CI: 2.75-6.22, P < .001) were observed in the IRI group. However, the incidences of grade 3/4 neutropenia (RR = 0.75, 95% CI: 0.68-0.83, P < .001), thrombocytopenia (RR = 0.43, 95% CI: 0.26-0.73, P = .002), and paresthesia/neurological disturbances (RR = 0.04, 95% CI: 0.02-0.07, P < .001) were higher in the OXA group.

CONCLUSION

This meta-analysis confirmed that the OXA ± bevacizumab regimen as a maintenance therapy significantly improved the ORR in patients with mCRC. Exhibiting strong efficacy and safety, the OXA and OXA plus bevacizumab regimens are preferred as first-line treatments for mCRC.

Multidisciplinary management of liver metastases in patients with colorectal cancer: a consensus of SEOM, AEC, SEOR, SERVEI, and SEMNIM

Colorectal cancer (CRC) has the second-highest tumor incidence and is a leading cause of death by cancer. Nearly 20% of patients with CRC will have metastases at the time of diagnosis, and more than 50% of patients with CRC develop metastatic disease during the course of their disease. A group of experts from the Spanish Society of Medical Oncology, the Spanish Association of Surgeons, the Spanish Society of Radiation Oncology, the Spanish Society of Vascular and Interventional Radiology, and the Spanish Society of Nuclear Medicine and Molecular Imaging met to discuss and provide a multidisciplinary consensus on the management of liver metastases in patients with CRC. The group defined the different scenarios in which the disease can present: fit or unfit patients with resectable liver metastases, patients with potential resectable liver metastases, and patients with unresectable liver metastases. Within each scenario, the different strategies and therapeutic approaches are discussed.

Anti-colorectal cancer effects of tripolinolate A from Tripolium vulgare

Tripolinolate A (TLA) is recently identified as a new compound from a halophyte plant Tripolium vulgare and has been shown to have significant in vitro activity against the proliferation of colorectal cancer and glioma cells. This study was designed to further investigate the effects of TLA on the proliferation of human normal cells, and the apoptosis and cell cycle in colorectal cancer cells, and the growth of tumors in the colorectal cancer-bearing animals. The data obtained from this study demonstrated that: 1) TLA had much less cytotoxicity in the human normal cells than the colorectal cancer cells; 2) TLA remarkably induced apoptosis in the human colorectal cancer cells and blocked cell cycle at G₂/M phase, and 3) TLA had significant anti-colorectal cancer activity in the tumor-bearing animals.

Stereotactic Body Radiotherapy (SBRT) for liver metastasis - clinical outcomes from the international multi-institutional RSSearch® Patient Registry

Background

Stereotactic body radiotherapy (SBRT) is an emerging treatment option for liver metastases in patients unsuitable for surgery. We investigated factors associated with clinical outcomes for liver metastases treated with SBRT from a multi-center, international patient registry.

Methods

Patients with liver metastases treated with SBRT were identified in the RSSearch® Patient Registry. Patient, tumor and treatment characteristics associated with treatment outcomes were assessed. Dose fractionations were normalized to BED₁₀. Overall survival (OS) and local control (LC) were evaluated using Kaplan Meier analysis and log-rank test.

Results

The study included 427 patients with 568 liver metastases from 25 academic and community-based centers. Median age was 67 years (31–91 years). Colorectal adenocarcinoma (CRC) was the most common primary cancer. 73% of patients received prior chemotherapy. Median tumor volume was 40 cm³ (1.6–877 cm³), median SBRT dose was 45 Gy (12–60 Gy) delivered in a median of 3 fractions [1–5]. At a median follow-up of 14 months (1–91 months) the median overall survival (OS) was 22 months. Median OS was greater for patients with CRC (27 mo), breast (21 mo) and gynecological (25 mo) metastases compared to lung (10 mo), other gastro-intestinal (GI) (18 mo) and pancreatic (6 mo) primaries (p < 0.0001). Smaller tumor volumes (< 40 cm³) correlated with improved OS (25 months vs 15 months p = 0.0014). BED₁₀ ≥ 100 Gy was also associated with improved OS (27 months vs 15 months p < 0.0001). Local control (LC) was evaluable in 430 liver metastases from 324 patients. Two-year LC rates was better for BED₁₀ ≥ 100 Gy (77.2% vs 59.6%) and the median LC was better for tumors < 40 cm³ (52 vs 39 months). There was no difference in LC based on histology of the primary tumor.

Conclusions

In a large, multi-institutional series of patients with liver metastasis treated with SBRT, reasonable LC and OS was observed. OS and LC depended on dose and tumor volume, while OS varied by primary tumor. Future prospective trials on the role of SBRT for liver metastasis from different primaries in the setting of multidisciplinary management including systemic therapy, is warranted.

Trial registration

Clinicaltrials.gov: NCT01885299.

A triplet combination with capecitabine/oxaliplatin/irinotecan (XELOXIRI) plus cetuximab as first-line therapy for patients with metastatic colorectal cancer: a dose escalation study

PURPOSE

The addition of cetuximab to triplet chemotherapy can increase treatment efficacy for patients with metastatic colorectal cancer (mCRC). We explored the dose-limiting toxicity and feasibility of a triweekly capecitabine, oxaliplatin, irinotecan, plus cetuximab (XELOXIRI plus cetuximab) regimen in patients with wild-type KRAS mCRC.

METHODS

Patients received oxaliplatin (100 mg/m², day 1), capecitabine (1700 mg/m² per day from day 2 to 15), irinotecan (100, 120, and 150 mg/m² for dose levels 1, 2, 3, respectively, on day 1), and cetuximab (400 mg/m², day 1 and, thereafter, 250 mg/m² every week), repeated every 3 weeks. Dose-limiting toxicities (DLTs) were assessed in the first 2 treatment cycles to determine the maximum tolerated dose (MTD) and the recommended dose (RD).

RESULTS

Twelve patients received a median of 7 cycles of therapy (range 2-10). The DLT was grade 4 neutropenia, observed in 1 of 6 patients at dose level 2. The MTD was not reached at dose level 3. Therefore, the RD of irinotecan was defined as 150 mg/m². Most common grade ≥ 3 toxicities were neutropenia (50%), diarrhea (17%), and febrile neutropenia (8%). The response rate was 83% (complete and partial response: 1 and 9 patient(s), respectively), including 4 conversion cases.

CONCLUSIONS

The combination of XELOXIRI and cetuximab is feasible and has an acceptable toxicity profile; neutropenia was the DLT. The RD of irinotecan is 150 mg/m². The observed response rate was promising and warrants further investigation.

Stereotactic Body Radiotherapy for Liver Metastases

Many cancers can spread to the liver, often as the sole site of metastatic disease. For properly selected patients with limited hepatic disease and good performance status, an aggressive strategy involving radical local therapy to the site(s) of metastasis offers a chance for extended disease-free survivorship. The development of stereotactic body radiotherapy has inserted radiation therapy into the arsenal of valuable treatment options in this clinical setting. This article summarizes the latest advancements in the use of stereotactic body radiotherapy to treat liver metastases.

Cost-Effectiveness of Treatment Sequences of Chemotherapies and Targeted Biologics for Elderly Metastatic Colorectal Cancer Patients

BACKGROUND

Treatment patterns for metastatic colorectal cancer (mCRC) patients have changed considerably over the last decade with the introduction of new chemotherapies and targeted biologics. These treatments are often administered in various sequences with limited evidence regarding their cost-effectiveness.

OBJECTIVE

To conduct a pharmacoeconomic evaluation of commonly administered treatment sequences among elderly mCRC patients.

METHODS

A probabilistic discrete event simulation model assuming Weibull distribution was developed to evaluate the cost-effectiveness of the following common treatment sequences: (a) first-line oxaliplatin/irinotecan followed by second-line oxaliplatin/irinotecan + bevacizumab (OI-OIB); (b) first-line oxaliplatin/irinotecan + bevacizumab followed by second-line oxaliplatin/irinotecan + bevacizumab (OIB-OIB); (c) OI-OIB followed by a third-line targeted biologic (OI-OIB-TB); and (d) OIB-OIB followed by a third-line targeted biologic (OIB-OIB-TB). Input parameters for the model were primarily obtained from the Surveillance, Epidemiology, and End Results-Medicare linked dataset for incident mCRC patients aged 65 years and older diagnosed from January 2004 through December 2009. A probabilistic sensitivity analysis was performed to account for parameter uncertainty. Costs (2014 U.S. dollars) and effectiveness were discounted at an annual rate of 3%.

RESULTS

In the base case analyses, at the willingness-to-pay (WTP) threshold of $100,000/quality-adjusted life-year (QALY) gained, the treatment sequence OIB-OIB (vs. OI-OIB) was not cost-effective with an incremental cost-effectiveness ratio (ICER) per patient of $119,007/QALY; OI-OIB-TB (vs. OIB-OIB) was dominated; and OIB-OIB-TB (vs. OIB-OIB) was not cost-effective with an ICER of $405,857/QALY. Results similar to the base case analysis were obtained assuming log-normal distribution. Cost-effectiveness acceptability curves derived from a probabilistic sensitivity analysis showed that at a WTP of $100,000/QALY gained, sequence OI-OIB was 34% cost-effective, followed by OIB-OIB (31%), OI-OIB-TB (20%), and OIB-OIB-TB (15%).

CONCLUSIONS

Overall, survival increases marginally with the addition of targeted biologics, such as bevacizumab, at first line and third line at substantial costs. Treatment sequences with bevacizumab at first line and targeted biologics at third line may not be cost-effective at the commonly used threshold of $100,000/QALY gained, but a marginal decrease in the cost of bevacizumab may make treatment sequences with first-line bevacizumab cost-effective. Future economic evaluations should validate the study results using parameters from ongoing clinical trials.

DISCLOSURES

This study was supported in part by a grant from the Agency for Healthcare Research and Quality (R01-HS018956) and in part by a grant from the Cancer Prevention and Research Institute of Texas (RP130051), which were obtained by Du. The authors report no conflicts of interest. Study concept and design were primarily contributed by Parikh, along with the other authors. All authors participated in data collection, and Parikh took the lead in data interpretation and analysis, along with Lairson and Morgan, with assistance from Du. The manuscript was written primarily by Parikh, along with Lairson, Morgan, and Du, and revised by Parikh.

c-MET inhibition enhances the response of the colorectal cancer cells to irradiation in vitro and in vivo

The aim of the present study was to investigate the effect of hepatocyte growth factor receptor (c-MET) inhibition on the viability of colon cancer cells and xenografts exposed to irradiation using short hairpin (sh)RNA or the c-MET inhibitor PHA665752. The underlying mechanisms were also investigated. Human colorectal adenocarcinoma HT-29 cells were infected with a lentivirus expressing shRNAs against c-MET and were irradiated at 0, 2, 4, 6 and 8 Gy. The viability of the cells was assessed by alamarBlue® assays. Mice bearing human colon carcinoma SW620 xenografts were randomly selected to receive 2.5% dimethyl sulfoxide (DMSO), 25 mg/kg PHA665752 intraperitoneally once every 2 days for 3 weeks, irradiation at 10 Gy, or 25 mg/kg PHA665752 intraperitoneally once every 2 days for 3 weeks followed 24 h later by irradiation at 10 Gy. The mean tumor volume (MTV) was measured. The apoptotic rate of cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assays, and double stranded break marker antibody γ-H2AX and hypoxia inducible factor (HIF)-1α expression was examined by immunohistochemistry. alamarBlue assays revealed that c-MET downregulation by shRNA markedly accentuated the irradiation-induced reduction in the viability of HT-29 cells compared with HT-29 cells irradiated at the same doses (P<0.05). A combination of irradiation and PHA665752 caused an additional reduction in the MTV (382.8±42.4 mm3; P<0.01 vs. irradiation and PHA665752, 998.0±180.6 and 844.8±190.0 mm3, respectively). TUNEL assays revealed that irradiation and PHA665752 alone caused significant apoptosis of the SW620 cells in the tumor xenografts (P<0.01 vs. DMSO). The apoptotic index in the tumor xenografts of mice treated with a combination of irradiation and PHA665752 was significantly increased compared with mice treated with either agent alone (P<0.01). The combination of irradiation and PHA665752 was also associated with a marked increase in γ-H2AX levels and a significant decrease in HIF-1α expression in the xenografts (P<0.01). In conclusion, c-MET inhibition sensitizes colorectal cancer cells to irradiation by enhancing the formation of DNA double strand breaks and possibly alleviating tumor hypoxia.

Patterns of Treatment Sequences in Chemotherapy and Targeted Biologics for Metastatic Colorectal Cancer: Findings from a Large Community-Based Cohort of Elderly Patients

Background

Over the last decade, multiple chemotherapies/targeted biologics have been approved for metastatic colorectal cancer (mCRC). However, evidence is limited with regards to the array of treatments received by mCRC patients.

Objective

This study examines treatment sequences (first- to third-line chemotherapy/targeted biologics) and the factors associated with first-line targeted biologics and common treatment sequences for elderly mCRC patients treated in a community setting.

Methods

A retrospective cohort study was conducted in mCRC patients diagnosed from January 2004 through December 2009 using the Surveillance, Epidemiology and End Results Medicare-linked database. The treatment sequences administered to elderly mCRC patients were empirically identified.

Results

Of 4418 mCRC patients who received treatment, 1370 (31 %) received first, second, and third line; 1164 (26 %) received first and second line; and 1884 (43 %) received only first line. The most common first line of treatment for mCRC patients was 5-fluorouracil/leucovorin + oxaliplatin (FOLFOX) + bevacizumab (23 %) and FOLFOX (23 %). 5-fluorouracil/leucovorin + irinotecan (FOLFIRI)-based regimens were commonly (22 %) administered in second line. The most common treatment sequence was first-line oxaliplatin or irinotecan followed by second-line oxaliplatin or irinotecan + bevacizumab followed by a third-line targeted biologic. Of patients who received first-line therapy, 47 % also received a targeted biologic, and the factors associated were age, comorbidity score, cancer site, geographic location, and year of diagnosis.

Conclusion

Elderly mCRC patients receive a multitude of treatments in various sequences. Further exploration of the comparative effectiveness of treatment sequences may yield important information for improving mCRC survival.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-015-0059-9) contains supplementary material, which is available to authorized users.

Bevacizumab in combination with fluoropyrimidine-irinotecan- or fluoropyrimidine-oxaliplatin-based chemotherapy for first-line and maintenance treatment of metastatic colorectal cancer

Despite a slight decrease in mortality rates, recent advances in screening methods, diagnosis and overall improved therapeutic options, colorectal cancer (CRC) remains among the leading causes of cancer-related death worldwide. The major cause is the mortality related to metastatic status of CRC. Increasing clinical evidence derived from randomized trials strongly suggests that the efficacy of standard cytotoxic agents, including various combinations of 5-fluoouracil (5-FU)/leucovorin (LV), capecitabine, irinotecan and oxaliplatin, may be significantly augmented with concomitant administration of molecular agents targeting the vascular endothelial growth factor (VEGF) signaling pathways, such as bevacizumab. Herein, we critically discuss the current data on the efficacy and safety profile of bevacizumab in combination with fluoropyrimidine-based chemotherapy for first-line and maintenance treatment of metastatic CRC and briefly comment on existing controversies and future perspectives.

Is more not better?: combination therapies in colorectal cancer treatment

The treatment of colorectal cancer has evolved dramatically in recent years with the availability of new chemotherapeutic agents and inhibitors of the vascular endothelial growth factor- and epidermal growth factor-signaling pathways. The incremental benefit of each individual line of therapy for advanced disease is relatively small. Advances in our ability to select patients should improve the cost-effectiveness of our treatment strategies (avoiding unnecessary toxicity in the patients who are unlikely to benefit and accepting the potential for adverse events in the patients who stand to benefit the most from a given regimen).

A dose-escalation study of oxaliplatin/capecitabine/irinotecan (XELOXIRI) and bevacizumab as a first-line therapy for patients with metastatic colorectal cancer

PURPOSE

The aim of this study was to determine the recommended dose (RD) of a triweekly capecitabine, oxaliplatin, irinotecan, and bevacizumab (XELOXIRI/bevacizumab) regimen that was easier to administer than FOLFOXIRI/bevacizumab, using capecitabine instead of 5-fuorouracil (5-FU), in patients with metastatic colorectal cancer (mCRC).

METHODS

Patients received oxaliplatin (100 mg/m(2), day 1), capecitabine (1,700 mg/m(2) per day from day 2 to 15), irinotecan (100, 120, 150 mg/m(2) for dose levels 1, 2, 3, day 1), and bevacizumab (7.5 mg/kg, day 1), repeated every 3 weeks. Dose-limiting toxicities (DLTs) were assessed in the first two cycles to determine the maximum tolerated dose (MTD).

RESULTS

Twelve patients received a median of 6.5 cycles of therapy (range 2-12). The DLT was grade 4 neutropenia, observed in one of six patients at dose level 2. The MTD was not reached at dose level 3. Therefore, the RD of irinotecan was defined as 150 mg/m(2). The most common grade ≥3 toxicities were neutropenia (41 %), anemia (17 %), diarrhea (8 %), and febrile neutropenia (8 %). The response rate and median progression-free survival were 83 % and 15 months, respectively.

CONCLUSIONS

XELOXIRI/bevacizumab is a feasible regimen for patients with mCRC, neutropenia was the DLT, and the RD of irinotecan is 150 mg/m(2). The response rate observed is very promising and warrants further investigation.

OATP1B1 and tumour OATP1B3 modulate exposure, toxicity, and survival after irinotecan-based chemotherapy

Background:

Treatment of advanced and metastatic colorectal cancer with irinotecan is hampered by severe toxicities. The active metabolite of irinotecan, SN-38, is a known substrate of drug-metabolising enzymes, including UGT1A1, as well as OATP and ABC drug transporters.

Methods:

Blood samples (n=127) and tumour tissue (n=30) were obtained from advanced cancer patients treated with irinotecan-based regimens for pharmacogenetic and drug level analysis and transporter expression. Clinical variables, toxicity, and outcomes data were collected.

Results:

SLCO1B1 521C was significantly associated with increased SN-38 exposure (P<0.001), which was additive with UGT1A1*28. ABCC5 (rs562) carriers had significantly reduced SN-38 glucuronide and APC metabolite levels. Reduced risk of neutropenia and diarrhoea was associated with ABCC2–24C/T (odds ratio (OR)=0.22, 0.06–0.85) and CES1 (rs2244613; OR=0.29, 0.09–0.89), respectively. Progression-free survival (PFS) was significantly longer in SLCO1B1 388G/G patients and reduced in ABCC2–24T/T and UGT1A1*28 carriers. Notably, higher OATP1B3 tumour expression was associated with reduced PFS.

Conclusions:

Clarifying the association of host genetic variation in OATP and ABC transporters to SN-38 exposure, toxicity and PFS provides rationale for personalising irinotecan-based chemotherapy. Our findings suggest that OATP polymorphisms and expression in tumour tissue may serve as important new biomarkers.

A phase IIa randomized, double-blind trial of erlotinib in inhibiting epidermal growth factor receptor signaling in aberrant crypt foci of the colorectum

Colorectal cancer progresses through multiple distinct stages that are potentially amenable to chemopreventative intervention. Epidermal growth factor receptor (EGFR) inhibitors are efficacious in advanced tumors including colorectal cancer. There is significant evidence that EGFR also plays important roles in colorectal cancer initiation, and that EGFR inhibitors block tumorigenesis. We performed a double-blind randomized clinical trial to test whether the EGFR inhibitor erlotinib given for up to 30 days had an acceptable safety and efficacy profile to reduce EGFR signaling biomarkers in colorectal aberrant crypt foci (ACF), a subset of which progress to colorectal cancer, and normal rectal tissue. A total of 45 patients were randomized to one of three erlotinib doses (25, 50, and 100 mg) with randomization stratified by nonsteroidal anti-inflammatory drug (NSAID) use. There were no unanticipated adverse events with erlotinib therapy. Erlotinib was detected in both normal rectal mucosa and ACFs. Colorectal ACF phosphorylated ERK (pERK), phosphorylated EGFR (pEGFR), and total EGFR signaling changes from baseline were modest and there was no dose response. Overall, this trial did not meet is primary efficacy endpoint. Colorectal EGFR signaling inhibition by erlotinib is therefore likely insufficient to merit further studies without additional prescreening stratification or potentially longer duration of use.